Starting instrumentation passes.
more built. weird crash
Got the sanitizers working with a hack of a way to add a DataLayout to
a PassManager. Bounds checking is still busted.
Got instrumentation up through bounds-checking working.
PassManager interface is still gross.
Got DebugIR passes working. Needed a fix to support null operands to
metadata nodes.
Merge branch 'master' into instrumentation
Cleanup. Simplify approach to PassSetSpecs.